Multi-layer porous film material

ABSTRACT

A surgical implant includes at least two porous film layers each having a plurality of pores. The porous film layers are in a stacked configuration and are interconnected to one another at a plurality of attachment points to define at least one void between the porous film layers.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application which claims thebenefit of and priority to U.S. patent application Ser. No. 13/690,445,filed on Nov. 30, 2012, the entire disclosure of which is herebyincorporated by reference herein.

BACKGROUND 1. Technical Field

The present disclosure relates to medical devices, and moreparticularly, to multi-layered porous films for use as surgicalimplants.

2. Background of Related Art

The use of medical devices, and more specifically, implants, is known.Surgical implants include, for example, meshes for hernia repair,buttresses for staple line reinforcement, patches and sealants forrepair of tissue defects and hemostasis, scaffolds for tissueintegration, and other wound closure and tissue repair devices. Theperformance requirements of each of these implants are different, andthus, the material and construction of these implants vary and arespecific to the surgical procedure being performed.

It would be advantageous to provide a surgical implant that can be usedin a variety of surgical applications, wherein the properties of eachlayer of the implant can be controlled by material selection, pore size,and pore distribution, and the layered construction of the implant canbe tailored to produce an implant having the desired mechanical strengthand tissue compatibility necessary for favorable host interaction.

SUMMARY

A surgical implant of the present disclosure includes at least twoporous substrates each having a plurality of openings. The poroussubstrates are in a stacked configuration and are interconnected to oneanother at a plurality of attachment points to define at least one voidbetween the porous substrates.

According to an aspect of the present disclosure, a surgical implantincludes a first porous film layer including a plurality of poreslayered on top of a second porous film layer including a plurality ofpores. The first and second porous film layers are interconnected to oneanother at a plurality of attachment points that define at least onevoid within the surgical implant between the first and second porousfilm layers. In embodiments, the attachment points are substantiallyevenly spaced about the surgical implant.

The first and second porous film layers may be fabricated from abiodegradable, a non-degradable material, or combinations thereof. Inembodiments, the first and second porous film layers are substantiallyplanar. In other embodiments, the first and second porous film layersmay be non-planar and shaped to conform to a specific tissue surface.The first and second porous film layers may have the same or a differentthickness, the same or a different elasticity modulus, and/or the sameor a different degree of porosity. In embodiments, the first and secondporous film layers may be uniaxially oriented in the same or differentdirections.

The surgical implant may include an adhesion barrier layer and/or anadhesion layer applied to an outer surface of the first and/or secondporous film layers. The adhesion barrier layer and adhesion layer may beprovided as films. The surgical implant may also include a fillermaterial disposed within the openings of the first porous layer, theopenings of the second porous film layer, and/or the voids between thefirst and second porous film layers. In embodiments, the filler materialis a drug. In some embodiments, the filler material is a hydrogel.

The surgical implant may include a third porous film layer including aplurality of pores. The third porous film layer is interposed betweenthe first and second porous film layers, and is interconnected by atleast one attachment point with at least one of the first and secondporous film layers.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing objects and advantages of the disclosure will become moreapparent from the reading of the following description in connectionwith the accompanying drawings, in which:

FIGS. 1A and 1B are perspective and cross-sectional views, respectively,of a surgical implant in accordance with an embodiment of the presentdisclosure;

FIG. 1C is a cross-sectional view of the surgical implant of FIGS. 1Aand 1B including a filler material in accordance with another embodimentof the present disclosure;

FIG. 2A is a perspective view of an embodiment of a surgical implant ofthe present disclosure for use with a circular surgical stapling device;

FIG. 2B is a front, perspective view of the surgical implant of FIG. 2A;

FIG. 3 is a perspective view of an embodiment of a surgical implant anda linear surgical stapling apparatus in accordance with anotherembodiment of the present disclosure;

FIG. 4 is a partial, cross-sectional view of a surgical implant inaccordance with a further embodiment of the present disclosure;

FIG. 5A is a partial, cross-sectional view of a surgical implant inaccordance with another embodiment of the present disclosure;

FIG. 5B is a partial, cross-sectional view of the surgical implant ofFIG. 5A including an adhesion barrier in accordance with an embodimentof the present disclosure;

FIG. 6 is a partial, cross-sectional view of a surgical implant inaccordance with yet still another embodiment of the present disclosure;

FIG. 7 is a perspective view of a surgical implant in accordance withanother embodiment of the present disclosure;

FIG. 8 is a cross-sectional view of a surgical implant in accordancewith yet another embodiment of the present disclosure; and

FIG. 9 is a cross-sectional view of a surgical implant in accordancewith another embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure is directed to a multi-layered implant includingat least two porous film layers joined at attachment points for use in avariety of surgical applications. The porous nature of the films and themulti-layered construction of the implant provide spaces for fluidtransfer and filling, tissue ingrowth, and loading of filler materials,such as drug or biologic factors.

The following discussion includes a description of the presentlydisclosed surgical implant and exemplary embodiments of construction anduse in accordance with the principles of the present disclosure. Thepresently disclosed surgical implants may be any medical device, such asscaffolds, grafts, patches, slings, pledgets, growth matrices, drugdelivery devices, wound plugs, and, in general, soft tissue repairdevices and surgical prostheses. It should be understood that the devicemay also be utilized as topically applied medical products, such aswound dressings, coverings, and the like, that can be used inmedical/surgical procedures.

Referring now to the figures, wherein like components are designated bylike reference numerals throughout the several views, FIGS. 1A and 1Billustrate a surgical implant 10 including at least two poroussubstrates 12 overlying one another, e.g., first porous film layer 12 aand second porous film layer 12 b. Each of the porous substrates 12includes openings 14, illustrated as openings 14 a and 14 b,respectively, such as pores, voids, or holes over at least a portion ofa surface thereof. The porous film layers 12 a and 12 b may be formed byany suitable process, such as cast extrusion, molding, co-extrusion, orblown film processes. While the surgical implant 10 of the presentdisclosure is formed solely from porous film layers, it is envisionedthat a surgical implant of the present disclosure may also include aporous substrate in the form of a foam or fibrous layer.

The porous substrates are fabricated from any biodegradable and/ornon-degradable material. The term “biodegradable” as used herein isdefined to include both bioabsorbable and bioresorbable materials. Bybiodegradable, it is meant that the material decomposes, or losesstructural integrity under body conditions (e.g., enzymatic degradationor hydrolysis), or is broken down (physically or chemically) underphysiologic conditions in the body, such that the degradation productsare excretable or absorbable by the body. Absorbable materials areabsorbed by biological tissues and disappear in vivo at the end of agiven period, which can vary, for example, from hours to several months,depending on the chemical nature of the material. It should beunderstood that such materials include natural, synthetic,bioabsorbable, and/or certain non-absorbable materials, as well ascombinations thereof.

Representative natural biodegradable polymers which may be used to forma porous substrate include: polysaccharides such as alginate, dextran,chitin, chitosan, hyaluronic acid, cellulose, collagen, gelatin, fucans,glycosaminoglycans, and chemical derivatives thereof (substitutionsand/or additions of chemical groups including, for example, alkyl,alkylene, amine, sulfate, hydroxylations, carboxylations, oxidations,and other modifications routinely made by those skilled in the art);catgut; silk; linen; cotton; and proteins such as albumin, casein, zein,silk, and soybean protein; and combinations such as copolymers andblends thereof, alone or in combination with synthetic polymers.

Synthetically modified natural polymers which may be used to form aporous substrate include cellulose derivatives such as alkyl celluloses,hydroxyalkyl celluloses, cellulose ethers, cellulose esters,nitrocelluloses, and chitosan. Examples of suitable cellulosederivatives include methyl cellulose, ethyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, hydroxybutyl methylcellulose, cellulose acetate, cellulose propionate, cellulose acetatebutyrate, cellulose acetate phthalate, carboxymethyl cellulose,cellulose triacetate, cellulose sulfate sodium salt, and combinationsthereof.

Representative synthetic biodegradable polymers which may be utilized toform a porous substrate include polyhydroxy acids prepared from lactonemonomers (such as glycolide, lactide, caprolactone, ε-caprolactone,valerolactone, and δ-valerolactone), carbonates (e.g., trimethylenecarbonate, tetramethylene carbonate, and the like), dioxanones (e.g.,1,4-dioxanone and p-dioxanone), 1,dioxepanones (e.g., 1,4-dioxepan-2-oneand 1,5-dioxepan-2-one), and combinations thereof. Polymers formedtherefrom include: polylactides; poly(lactic acid); polyglycolides;poly(glycolic acid); poly(trimethylene carbonate); poly(dioxanone);poly(hydroxybutyric acid); poly(hydroxyvaleric acid);poly(lactide-co-(ε-caprolactone-)); poly(glycolide-co-(ε-caprolactone));polycarbonates; poly(pseudo amino acids); poly(amino acids);poly(hydroxyalkanoate)s such as polyhydroxybutyrate,polyhydroxyvalerate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate),polyhydroxyoctanoate, and polyhydroxyhexanoate; polyalkylene oxalates;polyoxaesters; polyanhydrides; polyester anyhydrides; polyortho esters;and copolymers, block copolymers, homopolymers, blends, and combinationsthereof.

Some non-limiting examples of suitable non-degradable materials fromwhich a porous substrate may be made include: polyolefins such aspolyethylene (including ultra high molecular weight polyethylene) andpolypropylene including atactic, isotactic, syndiotactic, and blendsthereof; polyethylene glycols; polyethylene oxides; polyisobutylene andethylene-alpha olefin copolymers; fluorinated polyolefins such asfluoroethylenes, fluoropropylenes, fluoroPEGSs, andpolytetrafluoroethylene; polyamides such as nylon, Nylon 6, Nylon 6,6,Nylon 6,10, Nylon 11, Nylon 12, and polycaprolactam; polyamines;polyimines; polyesters such as polyethylene terephthalate, polyethylenenaphthalate, polytrimethylene terephthalate, and polybutyleneterephthalate; polyethers; polybutester; polytetramethylene etherglycol; 1,4-butanediol; polyurethanes; acrylic polymers; methacrylics;vinyl halide polymers such as polyvinyl chloride; polyvinyl alcohols;polyvinyl ethers such as polyvinyl methyl ether; polyvinylidene halidessuch as polyvinylidene fluoride and polyvinylidene chloride;polychlorofluoroethylene; polyacrylonitrile; polyaryletherketones;polyvinyl ketones; polyvinyl aromatics such as polystyrene; polyvinylesters such as polyvinyl acetate; etheylene-methyl methacrylatecopolymers; acrylonitrile-styrene copolymers; ABS resins; ethylene-vinylacetate copolymers; alkyd resins; polycarbonates; polyoxymethylenes;polyphosphazine; polyimides; epoxy resins; aramids; rayon;rayon-triacetate; spandex; silicones; and copolymers and combinationsthereof.

A porous substrate of a surgical implant of the present disclosure maybe provided in a variety of shapes and sizes to accommodate a variety ofdefects and tissue fascia that may need repair. Generally, a poroussubstrate is substantially planar and configured as a sheet that may bearranged in a layered or stacked configuration. A porous substrate,however, may, in embodiments, include non-planar surfaces that are sizedand shaped to conform to a tissue surface. A porous substrate can beproduced at a desired size and shape, or may be cut to a suitable sizeand shape for the envisaged application of use. A porous substrate maybe provided in a variety of thicknesses depending upon the propertiesdesired, e.g., stiffness and strength. In embodiments, a poroussubstrate (individual layer) may be from about 25 μm to about 500 μmthick, in some embodiments, from about 40 μm to about 250 μm thick, andin other embodiments, from about 50 μm to about 100 μm thick.

The openings in a porous substrate of a surgical implant of the presentdisclosure may be present as a surface characteristic or a bulk materialproperty, which partially or completely penetrates the porous substrate,and may be uniformly or randomly distributed across portions thereof. Insome embodiments, the openings do not extend across the entire thicknessof a porous substrate, but rather are present at a portion of thesurface thereof. Those skilled in the art reading the present disclosuremay envision a variety of distribution patterns and configurations ofthe openings in a porous substrate. It is envisioned that the poroussubstrate may, in embodiments, be partially or substantially non-porous.

The porous substrate may be rendered porous by any number of processes,including, for example, die rolling; laser micro-perforating; solventleaching of salt, sugar, or starch crystals; among other mechanical,electrical, and chemical processes within the purview of those skilledin the art. The openings of the porous substrate may be sized andconfigured to permit fibroblast through-growth and ordered collagenlaydown, resulting in integration of the surgical implant into the body.In embodiments, the openings may be from about 50 micrometers to about500 micrometers in diameter, in some embodiments, from about 100micrometers to about 400 micrometers in diameter, and in yet otherembodiments, from about 200 micrometers to about 300 micrometers indiameter. In embodiments, the openings may cover from about 20% to about80% of the area of a porous substrate, in some embodiments, from about30% to about 70% of the area, in yet other embodiments, from about 40%to about 60% of the area of a porous substrate. It should be understoodthat different thicknesses, weights, and porosities of a poroussubstrate may be selected by varying material selection andmanufacturing conditions.

Referring again to FIGS. 1A and 1B, first and second porous film layers12 a and 12 b are joined at spaced attachment points 16 to create voidsor pockets 18 between the first and second porous film layers 12 a and12 b. The first and second porous film layers 12 a and 12 b may bejoined by a number of bonding processes, including ultrasonic weldingand adhesive bonding, among other bonding techniques within the purviewof those skilled in the art. In embodiments, the attachment points 16are of substantially similar size and/or shape and may be positioned atsubstantially evenly spaced intervals across first and second porousfilm layers 12 a and 12 b, forming a plurality of voids 18 between thefirst and second porous film layers 12 a and 12 b. In some embodiments,the attachment points 16 may be provided around the entire periphery ofthe implant 10, forming a single, large void 18 between the first andsecond porous film layers 12 a and 12 b. In other embodiments, the size,shape, and/or position of the attachment points 16 may vary.

In embodiments, as illustrated in FIG. 1C, the openings 14 and/or voids18 may be loaded with filler material(s) 19, such as drugs or biologicfactors, among other secondary materials such as foams, hydrogels,adhesives, sealants, salts, sugars, etc. In embodiments, the fillermaterial 19 may fill about 5% to about 100% of the openings 14 and/orvoids 18 of the surgical implant 10, in some embodiments, from about 10%to about 80% of the openings 14 and/or voids 18, and in yet otherembodiments, from about 25% to about 75% of the openings 14 and/or voids18. The filler material 19 may be incorporated into the surgical implant10 during fabrication, or after the surgical implant 10 is formed. Theimplant or medical device can have spaced, intermittent attachmentpoints that are circular, linear, or have any shape. The attachmentpoints can form separate pockets in the implant or medical device, orrender the implant or medical device with a quilt-like configuration.

In embodiments, filler material 19 may include hydrogels which may beused as a means to absorb blood and as carriers of thrombogenic agentsfor blood clotting and hemostasis at wound sites. Hydrogels can bemodified with any number of conjugated molecules such as cell adhesionproteins, growth factors, peptides, and endogenous growth factorcapturing molecules, such as heparin sulfate, to promote tissue ingrowthand healing. In embodiments, the filler material 19 may includereleasable factors that have an associated binding interaction that willrelease agents by unbinding and diffusion, or filler materialdegradation.

Examples of filler materials 19 which may be utilized in accordance withthe present disclosure for example, include: anti-adhesives;antimicrobials; analgesics; antipyretics; anesthetics; antiepileptics;antihistamines; anti-inflammatories; cardiovascular drugs; diagnosticagents; sympathomimetics; cholinomimetics; antimuscarinics;antispasmodics; hormones; growth factors; muscle relaxants; adrenergicneuron blockers; antineoplastics; immunogenic agents;immunosuppressants; gastrointestinal drugs; diuretics; steroids; lipids;lipopolysaccharides; polysaccharides; platelet activating drugs;clotting factors; cancer treating chemical agents; and enzymes. It isalso intended that combinations of filler materials may be used.

Other filler materials 19 include: local anesthetics; non-steroidalantifertility agents; parasympathomimetic agents; psychotherapeuticagents; tranquilizers; decongestants; sedative hypnotics; steroids;sulfonamides; sympathomimetic agents; vaccines; vitamins; antimalarials;anti-migraine agents; anti-parkinson agents such as L-dopa;anti-spasmodics; anticholinergic agents (e.g., oxybutynin);antitussives; bronchodilators; cardiovascular agents, such as coronaryvasodilators and nitroglycerin; alkaloids; analgesics; narcotics such ascodeine, dihydrocodeinone, meperidine, morphine and the like;non-narcotics, such as salicylates, aspirin, acetaminophen,d-propoxyphene and the like; opioid receptor antagonists, such asnaltrexone and naloxone; anti-cancer agents; anti-convulsants;anti-emetics; antihistamines; anti-inflammatory agents, such as hormonalagents, hydrocortisone, prednisolone, prednisone, non-hormonal agents,allopurinol, indomethacin, phenylbutazone and the like; prostaglandins;cytotoxic drugs; chemotherapeutics, estrogens; antibacterials;antibiotics; anti-fungals; anti-virals; anticoagulants; anticonvulsants;antidepressants; antihistamines; and immunological agents.

Examples of yet other suitable filler materials 19 include: viruses andcells; peptides, polypeptides and proteins, as well as analogs, muteins,and active fragments thereof; immunoglobulins; antibodies; cytokines(e.g., lymphokines, monokines, chemokines); blood clotting factors;hemopoietic factors; interleukins (IL-2, IL-3, IL-4, IL-6); interferons(β-IFN, α-IFN and γ-IFN); erythropoietin; nucleases; tumor necrosisfactor; colony stimulating factors (e.g., GCSF, GM-CSF, MCSF); insulin;anti-tumor agents and tumor suppressors; blood proteins such as fibrin,thrombin, fibrinogen, synthetic thrombin, synthetic fibrin, syntheticfibrinogen; gonadotropins (e.g., FSH, LH, CG, etc.); hormones andhormone analogs (e.g., growth hormone); vaccines (e.g., tumoral,bacterial and viral antigens); somatostatin; antigens; blood coagulationfactors; growth factors (e.g., bone or nerve growth factor, insulin-likegrowth factor); bone morphogenic proteins; TGF-B; protein inhibitors;protein antagonists; protein agonists; nucleic acids, such as antisensemolecules, DNA, RNA, RNAi; oligonucleotides; polynucleotides; andribozymes. It is contemplated that the filler material can be releasedover time. The filler material may be released or degrade over time ormay be non-degradable.

Exemplary embodiments of construction and use of the present surgicalimplants are provided below. While embodiments are illustrated anddescribed with respect to specific surgical applications, it should beunderstood that the surgical implants may be used in any of a variety ofsurgical procedures, and that elements and features illustrate ordescribed in connection with one exemplary embodiment may be combinedwith elements and features of another exemplary embodiment.

Surgical implants of the present disclosure may be utilized in surgicalstapling procedures. As illustrated in FIGS. 2A and 2B, there isdisclosed an exemplary surgical stapling apparatus or surgical stapler100 (i.e., a circular stapler) for use in stapling tissue and applying asurgical implant, or surgical buttress 110, of the present disclosure totissue. Surgical stapling apparatus 100 generally includes a handleassembly 120 having at least one pivotable actuating handle member 122,and an advancing member 124. Extending from handle member 120, there isprovided a tubular body portion 126 which may be constructed so as tohave a curved shape along its length. Body portion 126 terminates in astaple cartridge assembly 130 which includes an annular array of stapleretaining slots 132 having a staple (not shown) disposed in each one ofstaple retaining slots 132. Positioned distally of staple cartridgeassembly 130 there is provided an anvil assembly 140 including an anvilmember 142 and a shaft 144 operatively associated therewith forremovably connecting anvil assembly 140 to a distal end portion ofstapling apparatus 100.

Reference may be made to commonly owned U.S. Pat. No. 5,915,616 to Violaet al., entitled “Surgical Fastener Applying Apparatus,” the entirecontents of which is incorporated herein by reference, for a detaileddiscussion of the construction and operation of an annular staplingdevice.

A surgical buttress 110, in accordance with the present disclosure, ispositioned about the shaft 144 of the anvil assembly 140. Surgicalbuttress 110 includes porous layers 112 each having openings 114disposed through at least a portion thereof, and a central aperture 113for positioning the surgical buttress 110 about the shaft 144 of theanvil assembly 140. It should be understood that while the surgicalbuttress 110 is shown as being associated with the anvil assembly 140,the surgical buttress 110 may, alternatively or additionally, beassociated with staple cartridge assembly 130. Surgical buttress 110 maybe configured into any shape, size, or dimension suitable to fit anysurgical stapling, fastening, or firing apparatus

Surgical buttress 110 is provided to reinforce and seal staple linesapplied to tissue by surgical stapling apparatus 100. The openings 114and/or voids (not shown, similar to voids 18) of the surgical buttress110 promote tissue ingrowth, and may fill with blood thereby improvingclot integration into the surgical buttress 110. The relatively thinconstruction of the porous film layers 112 renders the surgical buttress110 flexible and more easily penetrated by staples and a stapler knifeblade. As described above, the openings 114 and/or voids (not shown) ofthe surgical buttress 110 may be loaded with filler material(s).

FIG. 3 illustrates another exemplary surgical stapling apparatus orsurgical stapler 200 (i.e., a linear stapler) for use in stapling tissueand applying a surgical buttress 210 to the tissue. Surgical staplingapparatus 200 generally includes a handle 220 having an elongate tubularmember 222 extending distally therefrom. A jaw assembly 230 is mountedon a distal end 224 of elongate tubular member 222. Jaw assembly 230includes a staple clinching anvil jaw member 232 and a receiving jawmember 234 configured to receive a staple cartridge assembly 236. Jawassembly 230 may be permanently affixed to elongate tubular member 222or may be detachable and thus replaceable with a new jaw assembly 230.Staple clinching anvil jaw member 232 is movably mounted on distal end238 of jaw assembly 230 and is movable between an open position spacedapart from staple cartridge jaw member 234 to a closed positionsubstantially adjacent staple cartridge jaw member 234. A surgicalbuttress 210 is releasably attached to the staple cartridge assembly 234and/or the anvil jaw member 232.

Surgical stapling apparatus 200 further includes a trigger 226 movablymounted on handle 220. Actuation of trigger 226 initially operates tomove anvil jaw member 232 from the open to the closed position relativeto staple cartridge jaw member 234 and subsequently actuates surgicalstapling apparatus 200 to apply lines of staples to tissue. In order toproperly orient jaw assembly 230 relative to the tissue to be stapled,surgical stapling apparatus 200 is additionally provided with a rotationknob 228 mounted on handle 220. Rotation of rotation knob 228 relativeto handle 220 rotates elongate tubular member 222 and jaw assembly 230relative to handle 220 so as to properly orient jaw assembly 230relative to the tissue to be stapled.

A driver 250 is provided to move anvil jaw member 232 between the openand closed positions relative to staple cartridge jaw member 234. Driver250 moves between a longitudinal slot 252 formed in anvil jaw member232. A knife (not shown) is associated with driver 250 to cut tissuecaptured between anvil jaw member 232 and staple cartridge jaw member234 as driver 250 passes through slot 252.

Reference may be made to commonly owned U.S. Pat. Nos. 6,330,965 and6,241,139, each to Milliman et al. and entitled “Surgical StaplingApparatus,” the entire contents of each of which is incorporated hereinby reference, for a detailed discussion of the construction andoperation of a linear stapling device.

Surgical implants in accordance with the present disclosure may also beutilized to repair tissue defects, such as hernia repair procedures. Asillustrated in FIG. 4, a hernia repair device 310 includes a firstporous film layer 312 a, a second porous film layer 312 b, and a thirdporous film layer 312 c, each overlying one another. Each porous filmlayer 312 a-312 c includes openings 314 a-314 c, respectively. Thesecond porous film layer 312 b is sandwiched, or interposed, between thefirst and third porous film layers 312 a and 312 c. The first, second,and third porous film layers 312 a-312 c are joined at attachment points316 and define voids 318 between the successive layers. In embodiments,the second porous film layer 312 b may be fabricated from a materialhaving a higher modulus of elasticity than the first and third porousfilm layers 312 a and 312 c to create a stiffer material that may act asa reinforcing layer to the surgical implant 310, and minimize or preventimplant shrinkage that may occur with the use of fibrous hernia repairdevices. The first and third porous film layers 312 a and 312 c may befabricated from a more flexible material that is more pliant than thesecond porous film layer 312 b to reduce tissue abrasion and increasepatient comfort.

FIG. 5A illustrates an embodiment of a surgical implant includingvarying degrees of porosity. Surgical implant 410 includes a firstporous film layer 412 a configured to be placed against an abdominalwall, a second porous film layer 412 b, and a third porous film layer412 c configured to face the viscera. Each porous film layer 412 a-412 cincludes openings 414 a-414 c, respectively. The first porous film layer412 a includes a relatively larger degree of porosity to encouragetissue ingrowth therein, while the third porous film layer 412 cincludes a relatively smaller degree of porosity to discourage tissueingrowth and adhesion of tissue thereto. The second porous film layer412 b may include any degree of porosity.

In embodiments, as illustrated in FIG. 5B, the third porous film layer412 c may be coated with a hydrophilic adhesion barrier layer 411 formedfrom a quick dissolving or rapidly bioerodible polymeric material sothat any formed adhesion will detach from the surgical implant 410 oncethe adhesion barrier layer 411 dissolves. Examples of quick dissolvingor rapidly bioerodible polymer materials include water soluble polymerssuch as poly(lactide-co-glycolide)s, polyanhydrides, polyorthoesters,polyvinyl alcohol, hydroxylpropyl methylcellulose, and carboxymethylcellulose; biopolymers such as sugars, starches, salts, and gelatin; andderivatives and combinations thereof. In embodiments, the openings 414 aand/or voids 418 of the surgical implant 410 may be loaded with fillermaterials (not shown) as described above. In any of the embodimentsdescribed herein, the implant can have voids that have different kindsof filler materials inside. E.g., a hemostat in one pocket and a cancertreating agent in another pocket. For example, one would fill the firstpocket by capillary action, then dry the material, and then fill thesecond pocket with a different material.

It should be understood that while the attachment points are shown asuniting all of the layers of a surgical implant at a common point, theattachment points may be distributed in a variety of patterns, such asonly between two successive layers, between all stacked layers, andcombinations thereof. As illustrated in FIG. 6, for example, surgicalimplant 510 includes first and second porous film layers 512 a and 512 bjoined at attachment points 516 a and including voids 518 atherebetween. The third porous layer 512 c is attached to the secondporous layer 512 b at spaced attachment points 516 b joining all threelayers 512 a-512 c along, for example, a periphery of the surgicalimplant 510, thereby creating, if desired, larger voids 518 b betweenthe second and third porous film layers 512 b and 512 c. The attachmentpoints can be lines, dots, or have any shape.

Surgical implants in accordance with the present disclosure may also beutilized in reconstructive surgical procedures. As described above,mechanical properties of each porous layer, and thus the surgicalimplant, may be controlled by selecting, among other things, thematerials, thickness, and pore density of each porous film layer. Inembodiments, the production and assembly of the porous film layers maybe tailored to provide improved size retention, toughness, and strength.The films may be drawn, stretched, molded or extruded under conditions,e.g., heated, ambient, or cooled temperatures in a machine and/ortransverse direction, to produce films having different molecularorientation structures, and thus different film properties. The porouslayers, each having different axial polymer chain alignments, may bestacked to produce a surgical implant having strong tensile propertiesin multiple planes. For example, FIG. 7 illustrates a surgical implant610 including a first porous layer 612 a having molecules uniaxiallyoriented in a machine direction “M”, joined with a second porous layer612 b having molecules uniaxially oriented in a transverse direction“T”. It should be understood that a surgical implant may also includebiaxially-oriented films and/or films that have been incrementallystretched.

Surgical implants of the present disclosure may be utilized as scaffoldmaterials for tissue regeneration. In embodiments, the porous layers ofthe surgical implant may be optimized for strength to support loadbearing application and for cell attachment and ingrowth by providing acombination of porous layers of different thicknesses and surface areas.For example, FIG. 8 illustrates a surgical implant 710 including firstand third porous film layers 712 a and 712 c of substantially the samethickness “T1” and “T3” disposed on opposing sides of a second porousfilm layer 712 b having a thickness “T2”, that is greater thanthicknesses “T1” and “T3”. Openings 714 a and 714 b provide the firstand third porous film layers 712 a and 712 c with a textured surfacewith increased surface area for improved tissue integration.

In embodiments, the openings and/or voids may be loaded with fillermaterials, as discussed above. For example, the openings and/or voidsmay be loaded with adhesion protein or heparin sulfate conjugatedhydrogels or charged beads, that recruit specific cell types and growthfactors to encourage cellular ingrowth and maturation. The surgicalimplants may also be filled with growth factors or anti-inflammatorydrugs to improve tissue regeneration.

Surgical implants of the present disclosure may also be utilized forhemostasis. As illustrated in FIG. 9, a surgical implant 810 in the formof a hemostatic patch may include a first porous film layer 812 aconfigured to face a wound and a second porous film layer 812 b. Thefirst porous film layer 812 a may include an adhesive layer 811 to aidin the attachment of the surgical implant 810 to the wound. Inembodiments, the adhesive layer may be a reactive adhesive material thatincludes functional groups for binding or attaching the surgical implant810 to tissue by crosslinking with the reactive functional groupspresent in tissue, such as primary amine groups, secondary amine groups,hydroxyl groups, carboxylic groups, sulfonic groups, combinationsthereof, and the like. In embodiments, the reactive adhesive layer 811may be an in situ polymerizable hydrogel, e.g., commercially availableproducts such as FOCALSEAL® (Genzyme, Inc.), COSEAL® (AngiotechPharmaceuticals), and DURASEAL® (Confluent Surgical, Inc).

While the first porous film layer 812 a includes a sufficient number ofopenings 814 a to allow for blood to infiltrate the surgical implant810, such as through capillary or microfluidic filling, the secondporous film layer 812 b includes a minimal number and size of openings814 b to allow for the transfer of gases while encouraging bloodretention in the surgical implant 810. In embodiments, absorbentmaterials could be included in the openings 814 a, 814 b and/or voids818 of the surgical implant 810. Absorbent materials, e.g., hydrogels,allow collected blood and other wound fluid to gel and/or solidifythereby consolidating and containing these fluids in the surgicalimplant 810. Absorbent materials may swell during blood absorption,thereby exerting pressure on the wound to further reduce bleeding.

Surgical implants of the present disclosure may be utilized as a sealantor tissue patch, for example in duraplasty or lung sealant applications.As discussed with respect to FIG. 9 above, a first porous film layer 812a may include an adhesive material 811 for attachment to tissue, and asecond porous film layer 812 b may include a minimal number of openings814 b to provide a liquid sealed barrier. The porous film layers 812 aand 812 b would allow fluid filling or tissue ingrowth over time therebyencouraging integration into surrounding tissue.

In embodiments, a surgical implant may be fabricated with porous filmlayers that match the elastic behavior of the tissue in which thesurgical implant is placed. For example, in a lung sealing application,the porous film layers of a surgical implant may be formed ofelastomeric degradable polymeric materials, such as polyurethanes, tosubstantially match lung elasticity and to be distensible during lunginflation and retraction during breathing.

In any of the embodiments disclosed herein, the film material can be acombination of biodegradable materials, a combination of non-degradablematerials, or a combination thereof. In at least certain embodiments, itis preferred that both layers are made from biodegradable materials. Itis contemplated that each of the first porous film layer and secondporous film layers are both fabricated from at least one biodegradablematerial, from different biodegradable materials, from one biodegradablematerial and one non-biodegradable, or from at least twonon-biodegradable materials.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the presentdisclosure, but merely as exemplifications of embodiments thereof. Itwill be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications within thescope and spirit of the claims of the present disclosure.

1. (canceled)
 2. A surgical stapling apparatus comprising: a handleassembly; a tubular body portion extending from the handle assembly; astaple cartridge assembly extending from the tubular body portion; ananvil assembly coupled to the staple cartridge assembly and movablerelative thereto between open and closed positions; and a surgicalbuttress releasably attached to the staple cartridge assembly or theanvil assembly, the surgical buttress including first and second porousfilm layers successively stacked on each other and interconnected at aplurality of attachment points that define a plurality of pocketsbetween the first and second porous film layers.
 3. The surgicalstapling apparatus of claim 2, wherein the first and second porous filmlayers of the surgical buttress are substantially planar.
 4. Thesurgical stapling apparatus of claim 2, wherein the surgical buttressincludes a filler material disposed within at least one of the pluralityof pockets defined between the first and second porous film layers. 5.The surgical stapling apparatus of claim 4, wherein the filler materialis a drug.
 6. The surgical stapling apparatus of claim 4, wherein thefiller material is a hydrogel.
 7. The surgical stapling apparatus ofclaim 4, wherein the filler material is an adhesive.
 8. The surgicalstapling apparatus of claim 2, wherein the first and second porous filmlayers of the surgical buttress are bonded together at the plurality ofattachment points.
 9. The surgical stapling apparatus of claim 2,wherein the first porous film layer of the surgical buttress has a firstthickness and the second porous film layer of the surgical buttress hasa second thickness that is different from the first thickness.
 10. Thesurgical stapling apparatus of claim 2, wherein the first porous filmlayer of the surgical buttress has a first modulus of elasticity and thesecond porous film layer of the surgical buttress has a second modulusof elasticity that is different from the first modulus of elasticity.11. The surgical stapling apparatus of claim 2, wherein the first porousfilm layer of the surgical buttress has a first degree of porosity andthe second porous film layer of the surgical buttress has a seconddegree of porosity that is different form the first degree of porosity.12. The surgical stapling apparatus of claim 2, wherein the surgicalbuttress further includes an adhesive layer applied to an outer surfaceof the first or second porous film layers.
 13. The surgical staplingapparatus of claim 2, wherein the surgical buttress includes a centralaperture defined therethrough.
 14. The surgical stapling apparatus ofclaim 13, wherein the anvil assembly includes an anvil member and ashaft, the surgical buttress positionable on the shaft of the anvilassembly.
 15. The surgical stapling apparatus of claim 2, wherein thesurgical buttress further includes a third porous film layersuccessively stacked against the second porous film layer.
 16. Thesurgical stapling apparatus of claim 15, wherein each of the first andthird porous film layers of the surgical buttress has a first thicknessand the second porous film layer of the surgical buttress has a secondthickness that is greater than the first thickness.
 17. The surgicalstapling apparatus of claim 15, wherein the second porous film layer ofthe surgical buttress is fabricated from a material having a highermodulus of elasticity than materials of the first and third porous filmlayers of the surgical buttress.
 18. The surgical stapling apparatus ofclaim 15, wherein the third porous film layer of the surgical buttressis interconnected to the second porous film layer of the surgicalbuttress at a plurality of attachment points that define at least onepocket between the second and third porous film layers of the surgicalbuttress.
 19. The surgical stapling apparatus of claim 18, wherein theplurality of attachment points between the first and second porous filmlayers of the surgical buttress are different from the plurality ofattachment points between the second and third porous film layers of thesurgical buttress.